Edward Stewart's time lock, Stewart Time Lock Co., Fort Madison, Iowa - 2 movements

Back Up Next

Close up of the dual chain drive and weekly calendar mechanisms. An explanation and demonstration of how these work is illustrated in the video below. The brass plate indicates E. Howard made the time lock with the names of the company's co-owners, Samuel Atlee and Jacob Blackburn. (1) The central oval name plate has a patent date exactly one year in variance with the filed patent papers illustrated below. The diamond machined pattern is duplicated on the case, although it is somewhat faded. Howard used this design for other time lock makers who had turned to them for manufacture. Some examples are the Holms Electric Time Lock Co., Hollar Time Lock and Yale & Towne Manufacturing Co. While Stewart as well as Holms and Hollar were very short-lived companies, Yale survived to be, along with Sargent & Greenleaf, one of the largest and most prolific time lock makers. Yale used this pattern on most of their earlier nickel plated cases for decades. The camel back window design as well as the door hinge configurations of the Stewart are nearly identical to the Holms cases.


This video shows the dual fusee chain setting functions of the Edward Stewart time lock. These two independent setting systems allows the lock to operate as a conventional time lock allowing the opening of a safe once daily. The second chain, operated by the left crank, allows the lock to operate on an intraday basis. There is also a weekly calendar function that allows the lock to skip any one or number of days, for example in the case of a bank perhaps Saturday and/ or Sunday would be skipped.

The setting up of the lock is not easy and it's use is difficult to check. There are no indicators to let the user know how much duration is left on the time lock movements before they run down. In this case the user was expected to keep the movements running 24/7. They had a 56 hour duration and if allowed to run down would automatically put the time lock off guard. Most other time locks allow the user to set the time lock movements to operate only through the amount of time that one wanted the time lock to be on guard; allowing the movements to be at rest during the time the safe was meant to be open, resulting in a bit less wear and tear on the watch mechanisms.


Three quarter view and with case with time lock movement removed. 


The long metal strip serves as a fairly rudimentary shock absorber. Most time locks used some form of shock resistance from very early on. Once robbers knew that the safe could not be opened by the firm's personnel they turned to brute force. Without some form of cushion, the delicate balance wheels could easily become deranged or damaged resulting in a permanent lockout. Later most time locks employed springs split on both sides of the time lock movement plate for a far better shock resistance. The next photo shows the movement numbers as 101. Often the movement numbers began at 101 or in the case of the Consolidated Lock Co, 1001. The case also is stamped #1 leading me to believe this was the first production model made.


The front brass E. Howard plate removed. Next a close up of one of the movement balances and calendar wheel. Compare the similarity in design of the Stewart calendar wheel with that from an early Mosler calendar model introduced in 1881 and patented by Phinneas King in 1878, the same year as Stewart's patent.


Some minor repairs to the chain drives were needed upon arrival of the lock and one can see the mechanics of the chain drive here.

Below are the original patent papers filed by Edward Stewart.

One thing that stands out here is the fact that the patent papers show the patent date as August 13, 1878, but the engraving on the central name plate states "August 13, 1879". Surely this was an engraving error on the part of the E. Howard company. It is simply too coincidental of the year transposition to be anything else. The other four examples known to exist have this same error so it appears that the original and as it turned out only, order of twenty of these locks from E. Howard in 1882 all had the same mistake.

The Stewart time lock was available in both bolt-blocking (this example) and bottom-releasing formats. The late 1870's that saw a raft of new time lock designs patented and made, not only by smaller lock makers such as Lewis Lillie and Fredric North's New Britain Bank Lock, maker of the Pillard time lock, but tiny , new companies with little more than a new or good idea. One such design was was the Stewart time lock that let the mechanism lock and unlock automatically for a set period each day as well as intraday periods and skip its opening periods on the days set on the calendar wheel at the top center of the lock. (1) The Mosler calendar time lock could also perform all three functions.

Of the four known examples to have survived, all are the bolt-blocking type. One is in the Mossman gallery within the collection of the General Society of Mechanics and Tradesmen in New York City, one in the Harry C. Miller Museum in Kentucky and two in private hands. Movements #101, Case #1, 7"w x 4.25"h x 3"d. file #188


The first example is from the Harry Miller collection, missing front brass damascene plate, case has been replated. The second example is from the John M. Mossman collection.

(1)American Genius Nineteenth Century Bank Locks and Time Locks, David Erroll & John Erroll, pg. 198-199

Back Up Next